Bump.
1. Happens only with certain groups.

After being anywhere near these groups:

2. My toon is locked down for 5 or more seconds even with Immovability pot, break free, roll dodge and Purge (maybe it doesn't go off).

3. Will be stuck in loop:
"Left Combat", one second later "Entering Combat", stuck in combat for 30+ seconds. Repeats for 5 or more minutes.

When within range:

4. Ultimate and Skills won't fire. Even Light Attacks are delayed.

5. They take minuscule if any damage (usually they are not using shields or DODGE). Even if one or two are some distance from the others.

6. They do massive damage to my toon. 3x to 5x the amount per hit of other groups.

Bottom Line: They spend more time farming than playing the map, and the lack of normal groups of 20 - 24 players means they run havoc unopposed.